I spoke with your employee today.
He feels you are pressuring him on budget. You aren't listening. You are telling him what to do. He said, "Why doesn't he just do it then-why does he need me?" Your employee wants to do a good job. He takes time to build relationships- and he has some strong ones. He is reading business books since the training budget was cut - and well, you told him, "You can go if you get everything else done." He hired me to help him. He wanted guidance, support- someone on his side.
You see, this is your manager. You haven't trained him to be a supervisor; he is figuring it out. His employees love working for him and with him. He is the reason they feel valued by the organization. He is the reason they are engaged. They respect him. They don't know that you treat your manager as your assistant to clean up messes, and do what you don't want to do. They don't know that you flood his email box on Sunday night so he feels behind as he starts the week. You ask him questions about items he has already informed you about. You weren't listening. He was your top technical person, and you threw him into a supervisor job. He is doing so well, despite you. Others have noticed: another firm's leaders who met him at professional meetings. Those meetings which he attended and you never even asked about the topic or who he met. Do you even know he went or are you too busy? He was offered another position with that firm- without an interview. They know him, his values and his work. He knows them through these meetings. They grew professionally- together. They broke bread together. They laughed together. He knows they already value him. They already have a relationship.
He will give notice this week. He said, "The sad thing is that they won't really care because I just did the work. They wil notice when I bring over my employees." You see, you are losing a good technical person, an emerging supervisor and some of your good employees because who you work for -matters.
People want to work with people they know, like and trust. It isn't just one of those - it is all three. His employees will follow him.
You will be surprised that he resigns. Think about your reaction and learn from it. And think about it when members of his team leave. The surprise is because you didn't pay attention to him, or his needs. You didn't acknowledge his value. You didn't support his growth.
What you can do is learn from him. Don't cry to HR that is is due to more money. The conversation never starts there with a candidate. It is a relationship first-- always. Your lack of one created the opportunity. Good people aren't mercenaries - they want to contribute.